Quad band relay common data link system and method

ABSTRACT

A method of increasing reliability of a wireless radio includes: creating a first waveform at a first center frequency of an encoded data stream using a first wireless radio; creating a second waveform at a second center frequency of the encoded data stream using the first wireless radio; combining the first waveform and the second waveform into a composite waveform with redundant data streams at different center frequencies using the first wireless radio; wirelessly transmitting the composite waveform using the first wireless radio; wirelessly receiving the composite waveform; filtering the received composite waveform using a first filter band; digitizing the received composite waveform using the second wireless radio; demodulating the digitized composite waveform into a first data stream and a second data stream with the second wireless radio; and creating a third data stream representative of the encoded data stream.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser.No. 62/531,881 titled “High Speed Data Sampling For Filtering,Recreating GPS Signals, and High Speed Communications” filed on Jul. 13,2017 which is hereby incorporated by reference, in its entirety, for allit teaches and discloses.

FIELD OF THE INVENTION

The present invention discloses a quad band, common data link radiosystem and method.

BACKGROUND

The Common Data Link (CDL) system is a communication system that sufferssignificant performance and reliability losses due to multipathinterference and fading, particularly in low Angle of Arrival (AoA)operating conditions.

SUMMARY

A system and method of increasing reliability of a wireless radiocommunication includes: creating a first waveform at a first centerfrequency f₀ of an encoded data stream using a first wireless radio;creating a second waveform at a second center frequency f₁ of theencoded data stream using the first wireless radio; combining the firstwaveform and the second waveform into a composite waveform withredundant data streams at different center frequencies using the firstwireless radio; wirelessly transmitting the composite waveform using thefirst wireless radio; wirelessly receiving the composite waveform;filtering the received composite waveform using a first filter band;digitizing the received composite waveform using the second wirelessradio; demodulating the digitized composite waveform into a first datastream and a second data stream with the second wireless radio; andcreating a third data stream representative of the encoded data streamusing a combination of the first data stream and the second data streamusing the second wireless radio.

The communication system may further comprise: creating a third waveformat a third center frequency f₂ of an encoded data stream using the firstwireless radio, and creating a fourth waveform at a fourth centerfrequency f₃ of the encoded data stream using the first wireless radio.The communication system may further comprise wirelessly receiving theencoded data, with a third radio using a second filter band before thedigitizing step.

The method may additionally include: creating a first waveform at afirst center frequency f₀ of an encoded data stream using a firstwireless radio; creating a second waveform at a second center frequencyf₁ of the encoded data stream using the first wireless radio; creating athird waveform at a third center frequency f₂ of the encoded data streamusing the first wireless radio, and creating a fourth waveform at afourth center frequency f₃ of the encoded data stream using the firstwireless radio; combining the first waveform, the second waveform, thethird waveform, and the fourth waveform into a composite waveform withredundant data streams at different center frequencies using the firstwireless radio; wirelessly transmitting the composite waveform using thefirst wireless radio; wirelessly receiving the composite waveform;filtering the received composite waveform using a first filter band;digitizing the received composite waveform using the second wirelessradio; demodulating the digitized composite waveform into a first datastream, a second data stream, a third data stream and a fourth datastream with the second wireless radio; and creating a third data streamrepresentative of the encoded data stream using a combination of thefirst data stream, the second data stream, the third data stream, andthe fourth data stream using the second wireless radio;

The method may further comprise wirelessly receiving the encoded datastream, with a third wireless radio using a second filter band. Thefilter band may be a subset of the first filter band and the thirdwireless radio may decode the encoded data stream without using thefirst filter band. The method may further comprise subjecting the secondwireless radio and the third wireless radio to multipath interferencesignals, low angle of arrival signals, and/or jamming signals to jam theencoded signal of the third wireless radio without jamming the encodedsignal of the second wireless radio. The method may further comprisedetermining a line-of-sight condition for the third wireless radio andthe second wireless radio. The method may further comprise choosing aspecific satellite or aerial transmitter as the first wireless radiobased on the determined line-of-sight conditions. The specific satelliteor aerial transmitter may be chosen to keep the third wireless radiofrom receiving and decoding the encoded data stream. The method specificsatellite or aerial transmitter may be chosen to allow both of the thirdwireless radio and the second wireless radio to receive and decode theencoded data stream.

The Common Data Link performance and reliability is improved via theQuad band Relay (QbR) upgrade of legacy hardware. Multipath interferenceand fading effects are reduced by employing frequency diversity and dataredundancy. Previous critical fading that resulted in extended data lossand tracking loop-lock failures are significantly improved. The Quadband Relay architecture is an efficient hardware and digital signalprocessing (DSP) enhancement to legacy communication systems, The newwaveform transmitted by an upgraded QbR-CDL radio is 100% legacycompatible, while simultaneously providing link diversity when coupledwith an upgraded receiver. Frequency diversity is the optimal solutionto mitigate multipath interference and fading because those impairmentsare functions of frequency.

Utilizing an efficient frequency diversity architecture, link-loss dueto multipath is significantly reduced. This is due to the fact themultipath losses are frequency dependent, and QbR's redundanttransmissions have offset frequency centers transmitting encodedversions of the original legacy waveform. Legacy systems communicatewith QbR upgraded platforms seamlessly. Furthermore, QbR upgradedsystems receive the same transmission and are able to extract additionallink gains via processing.

A Quad band Relay utilizes available CDL bandwidth for diversitytransmission of multiple legacy waveforms. Frequency diversity is theoptimal solution to mitigate multipath interference and fading becausethose impairments are functions of frequency.

We approach a solution to improve CDL reliability using the frequencydiversity method, while maintaining a strict adherence to legacycompatibility requirements. We logically review the several possibleradio-version combinations to ensure valid legacy and diversitycommunications. Finally, we analyze performance for the three missionenvironments previously discussed—severe, moderate, and clear multipathchannels. All analysis is performed using the br45 waveform; however,the br10.71 QbR upgrade is proportionally identical in implementationand performance.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of the invention will be readilyunderstood, a more particular description of the invention brieflydescribed above will be rendered by reference to specific embodimentsillustrated in the appended drawings. Understanding that these drawingsdepict only typical embodiments of the invention and are not thereforeto be considered limiting of its scope, the invention will be describedand explained with additional specificity and detail through use of theaccompanying drawings, in which:

FIG. 1 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 2 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 3 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 4 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 5 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 6 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 7 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 8 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 9 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 10 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 11 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 12 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 13 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 14 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 15 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 16 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 17 shows a quad band relay example in accordance with an embodimentof the invention;

FIG. 18 shows a quad band relay example in accordance with an embodimentof the invention; and

FIG. 19 shows a quad band relay example in accordance with an embodimentof the invention.

DETAILED DESCRIPTION

It will be readily understood that the components of the presentinvention, as generally described and illustrated in the Figures herein,could be arranged and designed in a wide variety of differentconfigurations. Thus, the following more detailed description of theembodiments of the invention, as represented in the Figures, is notintended to limit the scope of the invention, as claimed, but is merelyrepresentative of certain examples of presently contemplated embodimentsin accordance with the invention. The presently described embodimentswill be best understood by reference to the drawings.

In FIG. 1, the power spectrum H0 centered at fb0, represents a legacybr45 waveform. The neighboring bandwidth is populated with 3 encodedversions of the legacy waveform—H1, H2, and H3. This bandwidth isgenerally unoccupied during legacy br45 operation; however, this QbR(quad-band relay) utilizes this available bandwidth to achieve diversitygain by modulating and channelizing (or up-converting) redundantversions of H0. The four spectrally offset waveforms now span the br274filter bandwidth, with band centers—fb0, fb1, fb2, and fb3. Legacy andQbR upgraded CDL systems interoperate seamlessly. Furthermore, QbRupgraded systems may perform additional diversity gain processing whencoupled with other upgraded systems. A legacy receiver's default br45analog filter path rejects the out-of-band QbR waveforms [H1, H2, andH3], receiving only H0—a 100% legacy waveform. On the other hand, a QbRreceiver's upgraded firmware selects the br274 filter path, allowing thelegacy waveform and the three diversity encoded neighbors to bedigitized, demodulated, and combined, resulting in one final br45 datastream. Deep fades (˜40 dB) are mitigated via QbR's diversity pathoptimal combining of the 4 demodulated signals, resulting in 20 dB+ fadeimprovements.

FIG. 2 illustrates the multipath fading of H0-H3. In this example, H2experiences mild 6 dB fades, while H0 approaches −40 dB nulls.Simplistically, the combining algorithm “prefers” the mild fading of H2,resulting in 15 to 34 dB improvement over H0. In addition to link gains,the QbR upgrade is 100% legacy compatible, simultaneously operational.Utilizing an efficient frequency diversity architecture, link-loss dueto multipath is significantly reduced. This is due to the fact themultipath losses are frequency dependent, and QbR's redundanttransmissions have offset frequency centers transmitting encodedversions of the original legacy waveform. Legacy systems communicatewith QbR upgraded platforms seamlessly. Furthermore, QbR upgradedsystems receive the same transmission and are able to extract additionallink gains via processing. An unmodified CDL system's default br45filter bank rejects the redundancy of QbR, thus receiving a 100% legacywaveform. On the other hand, a QbR receiver's firmware selects the br274filter path, allowing the legacy waveform and 3 diversity encodedwaveforms to be digitized, demodulated, and combined into one final br45data stream. Only the IF receiver filter bank selection changes, as faras the hardware is concerned. Upgrading the sea of current CDL hardwarehas been a key consideration in developing the QbR architecture, and thetwo enabling criteria which determine upgradability are: 1) The presenceof a br274 filter path, and 2) sufficient processing power (FPGA size).The later requirement is likely satisfied if the system supports, or wasoriginally designed to support the br274 waveform (regardless of br274functionality). Beyond basic legacy support, the QbR architectureenables legacy activity while simultaneously providing QbR linkdiversity. This support for simultaneous link activity makes the QbRupgrade of legacy systems a low-risk/high-return win for the CDLcommunity. QbR diversity performance gains are similarly achieved inbr10.71 links.

Differences between radios that receive legacy signals and radios thatreceive composite QBR signals may be used as a tool to selectivelycommunicate with a selected radio based on line-of-sight, multi-pathfading characteristics, and angle of arrival characteristics. A radiotransmitter source may be chosen to communicate with both a legacy radiosystem and a composite QBR system or with just the QBR system based apositioning of the radio transmitter source or a selection of asatellite source or other aerial vehicle radio transmission source.

In FIG. 3, gains can be (proportionally) extended to br10.71 waveforms,using the br45 analog filter bank to support the additional bandwidth.In other words, just as QbR distributes 4 encoded version of a br45waveform within a br274 filter bandwidth, four encoded br10.71 waveformscan similarly be distributed within a br45 bandwidth.

In FIG. 4, performance and implementation details are proportionallyidentical between br10.71 and br45 upgraded systems. Infrastructurediscussion is limited to system-level hardware functions and the DSPblocks needed for modulation and demodulation of CDL waveforms. Thesebasic CDL transmitter and receiver blocks are illustrated in FIG. 4. Theleft most block, the bit processing block, is assumed to completelymanage all binary operations preceding modulation—multiplexing, errorcorrection coding, synchronization bit insertion, cryptography, etc.Next, the modulator shapes the binary stream into a complex OQPSKwaveform. The waveform may be complex baseband centered, or digitallyup-converted to a complex IF when presented to the DAC. The DAC convertsthe digital waveform into an analog signal to be filtered by a softwareselectable filter bank for image rejection and, in some cases,additional shaping of the waveform. Finally the signal is up-convertedto Ku-band, amplified, and radiated into the air interface. The receiverperforms complementary operations: amplification, down-conversion,filtering, digitization and demodulation, followed by bit management.The selectable filter bank consists of several fixed bandwidth filterswhich can be selected in software, generally as a function of the datarate. These filters remove digital to analog converter spectral imagesand may contribute additional waveform shaping.

In FIG. 5, a simple filter bank can be seen on the left and relativefilter bandwidths are illustrated on the right. The function of thesefilters has changed, but they are generally available in all CDL modems.The key use of such filters in older systems was to shape andbandwidth-limit the signal. This was an essential function when DSPcapacity was minimal in the early years of the CDL system. Modern radiosare capable of shaping the waveform in the digital domain, and only usethe filter banks to remove spectral images resulting from the digital toanalog conversion. It is important to note that the spectral images(separated by the sample rate of the DAC) can be moved farther andfarther away from the desired signal by increasing the update rate ofthe DAC. The implication is that a digitally shaped waveform doesn'trequire a “tight” analog filter for additional analog shaping orbandwidth limiting, if the signal is sufficiently oversampled. Forexample, a highly oversampled br10.71 waveform may utilize a br274filter path and completely remove all spectral images. We use thisfeature to enable the QbR architecture.

In FIG. 6, the modulator and demodulator blocks are treated as“black-box” DSP functions, with a binary data stream input and acontinuous band-limited modulated waveform as an output. The binary dataprovided by the “bit-processing” block is the final result of alldigital multiplexing, error coding, randomizing, interleaving,encryption, etc. No additional binary operations are allowed. Similarly,the modulator output to the DAC is assumed to be the final waveform. Themodulator (or demodulator) can now be treated as a black box, implyingthat we can change anything within that box as long as nothing appearsto change on the outside. This is the second enabling feature of QbR.Common mission environments are described to better understand thepositioning of the link radios and potential physical features anddynamics that effect RF wave propagation.

Three link environments that result in a broad range of channelconditions. Given these link conditions, we describe the potentialinterference that may result in both static and dynamic channels. Adynamic channel implies at least one of the radios is moving at 50+ kmh.While free space propagation loss is important, we focus instead onmultipath losses and fading under these conditions. The losses due tomultipath can be significantly mitigated; while free space propagationlosses are fixed functions of link separation. The first missionenvironment has an air-vehicle and a ground unit separated by a largehorizontal distance, but both equipped with directional antennas. Thesecond mission configuration is between an air vehicle and a groundunit, neither have directional antennas. Finally, the third arrangementis between the same air and ground entities of example 1, but thehorizontal separation is small.

Multipath: When a transmitted signal arrives at a receiver by more thanone single path, the resulting composite signal is a multipath signal.The severity of multipath depends on the relative magnitudes, phases,and quantity of the received signals. The severity of multipathinterference and fading increases quickly as the geometric linkseparation increases, and the RF path's relative angles of arrival (AoA)decrease.

FIG. 8 illustrates the AoA decrease ( ) as the link separation increases(horizontally). This condition often results in multiple beam pathscombining at the Rx antenna with very small relative amplitudedifferences, but significant phase shifts. Thus, as free-spacepropagation losses worsen, multipath interference and fading severitypeaks. Multipath interference mitigation techniques: Adaptiveequalization and increased transmit power (link margin) are commontechniques to reduce the impact of mild multipath interference. Thesesolutions are effective if the channel is static, or changes veryslowly; however, for the air-ground mission conditions we areconsidering, the channel is changing very fast. Adaptive equalization iseffective for slowly varying channel conditions; however, thesignificant rate of variation of air-ship multipath components,(interaction of incident paths, their relative phases, and amplitudes)make adaptive equalization essentially useless in the dynamic multipathenvironment associated with small AoA link conditions. Common missionenvironments are described to better understand the positioning of thelink radios and potential physical features and dynamics that effect RFwave propagation. We describe three link environments that result in abroad range of channel conditions. Given these link conditions, wedescribe the potential interference that may result in both static anddynamic channels. A dynamic channel implies at least one of the radiosis moving at 50+ kmh. While free space propagation loss is important, wefocus instead on multipath losses and fading under these conditions. Thelosses due to multipath can be significantly mitigated; while free spacepropagation losses are fixed functions of link separation.

In FIG. 8, the Angle of Arrival decreases as link separation increases.Smaller AoA increase multipath interference. Multipath interferencemitigation techniques: Adaptive equalization and increased transmitpower (link margin) are common techniques to reduce the impact of mildmultipath interference. These solutions are effective if the channel isstatic, or changes very slowly; however, for the air-ground missionconditions we are considering, the channel is changing very fast.

Adaptive equalization is effective for slowly varying channelconditions; however, the significant rate of variation of air-shipmultipath components, (interaction of incident paths, their relativephases, and amplitudes) make adaptive equalization essentially uselessin the dynamic multipath environment associated with small AoA linkconditions.

In FIG. 9, a simple br45 fade profile with 3 reflected paths, resultingin 35 dB+ nulls. Equal-power QbR diversity provides the same link gainwith an additional 20 dB+ power margin compared to a legacy system.

FIG. 10 illustrates fade depths of 40+ dB. Also, FIG. 11 providesinsight as to the variance of the fade depths, which is an importantconsideration as the link margin should cover the most severe fading,which is up to 20+ dB additional margin. Asking 60 dB power increase outof a PA is not realistic. This topic is discussed in detail in reports 2and 3, with hardware results in report-4.

FIG. 10 shows a multipath fade severity and free space propagationlosses vs. decreasing AoA.

FIG. 11 shows a multipath fade variance with decreasing AoA. The problemis how to improve CDL performance and reliability, while maintaininglegacy compatibility. Maintaining legacy compatibility prohibits anypotential binary coding gains, particularly in the case of encryptedtransmissions. Furthermore, the waveforms are strictly-defined,eliminating more efficient or robust alternatives. For our solution tobe truly useful, simultaneous legacy and diversity mode communicationsshould be supported. Finally, the new architecture must fit within amajority of current hardware links, already in the field, with only afirmware upgrade. In summary the problems addressed, which must ALL besolved simultaneously, are: Mitigate the effects of multi-path fadingand interference; maintain 100% legacy compatibility; and supportsimultaneous legacy and diversity (QbR) communications.

Frequency diversity is used to increase the number of independent links“seen” by a Quad band Relay upgraded receiver. Quad band Relay utilizesavailable CDL bandwidth for diversity transmission of multiple legacywaveforms. In FIG. 12, the power spectrum H0 centered at fb0, representsa legacy br45 waveform. The neighboring bandwidth is populated with 3encoded versions of the legacy waveform—H1, H2, and H3. This bandwidthis generally unoccupied during legacy br45 operation; however, QbRutilizes this bandwidth to achieve diversity gain by modulating andchannelizing (or up-converting) redundant versions of H0. The fourspectrally offset waveforms now span the br274 filter bandwidth, withband centers—fb0, fb1, fb2, and fb3.

In FIG. 12, the QbR spectrum consists of FOUR br45 waveforms. Legacyspectral compatibility is still maintained, even though FIG. 12 appearsto violate CDL waveform specifications. It is true that the waveform ofFIG. 12 appears incorrect; however, when this waveform is subsequentlyreceived by a legacy receiver, the receiver “sees” only the spectrumpassed by the selected filter, as illustrated in FIG. 5. The br45 filterpath would be selected and the resultant digitized spectrum seen insidethe modem would appear, and would be, 100% legacy compliant.

FIG. 13 shows post br45 filtering results in a single legacy waveform.Legacy and QbR upgraded CDL systems interoperate seamlessly. The DSPfunctions that convert legacy CDL into QbR CDL are contained within theFPGA. The neighboring waveforms are rejected by the br45 filterstop-band, as shown.

FIG. 14 illustrates the additional DSP modulators that convert a legacyCDL transmitter into a QbR CDL transmitter.

We next logically verify the various combinations of QbR and legacyradios that may be on either side of a link at any given time. Allpotential combinations must maintain legacy compatibility andsimultaneously allow diversity gain. We analyze the various arrangementsby including the corresponding spectra seen just after the selectablefilter bank.

FIG. 15 illustrates a simplified br45 transmission, and the timebaseband time series. The modulated waveform is transmitted out of thebr45 filter-bank, up-converted to RF and radiated via a high-poweramplifier and antenna. That transmission is received in a like manner,via a LNA, down-converter and filtered by the br45 receive analogfilter.

FIG. 15 shows a standard br45 transmitter and receiver blocks andrespective waveforms (H0) The simple functions of FIG. 15 are extendedto form the QbR architecture by utilizing 3 additional modulators totransmit on 3 additional subcarriers. Note that these additional DSPfunctions are wholly confined to the FPGA domain.

FIG. 16 illustrates this operation for a QbR transmitter and receiver.In hardware, the only distinguishing variation (from br45 in FIG. 15) isthe selection of the br274 filter path, instead of the usual br45 path.This selection is made in software via a command to the RF switches toroute the analog signal to a particular filter.

FIG. 16 shows QbR diversity transmit and receive blocks and spectrum. Wenow see the transmit channel modulating the waveform H0, and threeadditional br45 modulations offset to neighboring channels. Thecomposite QbR waveform now propagates the wider bandwidth br274 filterpath. Similarly, the QbR receiver selects the same br274 filter path,and demodulates four independent br45 waveforms. The multi-channelfrequency offsets are achieved via efficient channelizer architectures.The channelization architecture is discussed in report-2. We nowconsider a QbR transmitter and legacy CDL receiver. The QbR radiates 4waveforms; however, the receiver is expecting only one—H0. Fortunately,when the QbR waveforms are received and down-converted, the br45 filterpath rejects the out-of-band waveforms. The digital demodulator iscompletely unaware of signal composition prior to the br45 filter.

FIG. 17 illustrates this architecture and spectral composition. FIG. 17QbR diversity transmit and legacy receive blocks and spectrum Anothercommon mode is when a QbR receiver demodulates a legacy transmission. Inthis case the anticipated redundant waveform will be absent. The QbRreceiver simply selects H0 as the optimal channel (since H1-H3 areabsent). QbR systems do not require additional information beyond thatavailable to legacy systems. Finally, simultaneous operation of QbR andlegacy systems is illustrated in FIG. 18. The presence of thetransmitted QbR waveform is useful to QbR receivers, but irrelevant tolegacy receivers.

FIG. 18 shows QbR diversity transmit and both QbR and legacy receiversmission environments analysis: The improvements QbR diversity achievesversus standard CDL are analyzed (see Results section) in three commonair-to-ship mission environments, detailed below and illustrated in.

In FIG. 19, severe multipath with weak line-of-sight path (LOS). This iscommon at a ground terminal when the link separation is greatest and theangle of arrival (AoA) is small. Moderate multipath with relativelystrong LOS path. This is often the case at an airborne receiver when theground-unit's transmit antenna has poor directionality. Negligiblemultipath and strong LOS signal. This is often the case at an airbornereceiver when the ground-unit has a highly directional antenna, and/orhas a large AoA. Also common at the ground terminal when the AoA islarge and the ground terminal antenna has good directionality.

The systems and methods disclosed herein may be embodied in otherspecific forms without departing from their spirit or essentialcharacteristics. The described embodiments are to be considered in allrespects only as illustrative and not restrictive. The scope of theinvention is, therefore, indicated by the appended claims rather than bythe foregoing description. All changes which come within the meaning andrange of equivalency of the claims are to be embraced within theirscope.

The invention claimed is:
 1. A method of increasing reliability of awireless radio communication system comprising: creating a firstwaveform at a first center frequency f₀ of an encoded data stream usinga first wireless radio; creating a second waveform at a second centerfrequency f₁ of the encoded data stream using the first wireless radio;creating a third waveform at a third center frequency f₂ of the encodeddata stream using the first wireless radio; creating a fourth waveformat a fourth center frequency f₃ of the encoded data stream using thefirst wireless radio; combining the first waveform, the second waveform,the third waveform, and the fourth waveform into a composite waveformwith redundant data streams at different center frequencies using thefirst wireless radio; wirelessly transmitting the composite waveformusing the first wireless radio; wirelessly receiving the compositewaveform with a second wireless radio; filtering the received compositewaveform using a first filter band with the second wireless radio;digitizing the received composite waveform using the second wirelessradio; demodulating the digitized composite waveform into a first datastream, a second data stream, a third data stream, and a fourth datastream with the second wireless radio; creating a final data streamrepresentative of the encoded data stream using a combination of two ormore of the first data stream, the second data stream, the third datastream, or the fourth data stream using the second wireless radio;wirelessly receiving the encoded data stream with a third wireless radiousing a second filter band that is a subset of the first filter band;and decoding the encoded data without using the first filter band. 2.The method of claim 1 further comprising: subjecting the second wirelessradio and the third wireless radio to multipath interference signals,low angle of arrival signals, and/or jamming signals to jam the encodedsignal of the third wireless radio without jamming the encoded signal ofthe second wireless radio.
 3. The method of claim 1 further comprising:determining a line-of-sight condition for the third wireless radio andthe second wireless radio.
 4. The method of claim 3 further comprising:choosing a specific satellite or aerial transmitter as the firstwireless radio based on the determined line-of-sight conditions.
 5. Themethod of claim 4, wherein the specific satellite or aerial transmitteris chosen to keep the third wireless radio from receiving and decodingthe encoded data stream.
 6. The method of claim 4, wherein the specificsatellite or aerial transmitter is chosen to allow both of the thirdwireless radio and the second wireless radio to receive and decode theencoded data stream.